diff --git modules/simpletest/tests/menu.test modules/simpletest/tests/menu.test
index 000929e..deafb29 100644
--- modules/simpletest/tests/menu.test
+++ modules/simpletest/tests/menu.test
@@ -928,7 +928,7 @@ class MenuBreadcrumbTestCase extends MenuWebTestCase {
   }
 
   function setUp() {
-    parent::setUp(array('menu_test'));
+    parent::setUp();
     $perms = array_keys(module_invoke_all('permission'));
     $this->admin_user = $this->drupalCreateUser($perms);
     $this->drupalLogin($this->admin_user);
@@ -1419,6 +1419,22 @@ class MenuTrailTestCase extends MenuWebTestCase {
 
   function setUp() {
     parent::setUp();
+    $perms = array_keys(module_invoke_all('permission'));
+    $this->admin_user = $this->drupalCreateUser($perms);
+    $this->drupalLogin($this->admin_user);
+
+    // This test puts menu links in the Navigation menu and then tests for
+    // their presence on the page, so we need to ensure that the Navigation
+    // block will be displayed in all active themes.
+    db_update('block')
+      ->fields(array(
+        // Use a region that is valid for all themes.
+        'region' => 'content',
+        'status' => 1,
+      ))
+      ->condition('module', 'system')
+      ->condition('delta', 'navigation')
+      ->execute();
 
     // This test puts menu links in the Management menu and then tests for
     // their presence on the page, so we need to ensure that the Management